1. Field of the Invention
The invention relates to an ice making system for a refrigerator and more particularly to an optic control system for an ice making system for use in a freezer compartment of a refrigerator.
2. Description of Related Art
Automatic ice making systems for use in a home refrigerator are well known. Typically, ice making systems include an ice maker mounted within the freezer compartment of the refrigerator and an ice storage receptacle or bin supported beneath the ice maker for receiving the formed ice from the ice maker. The ice maker is commonly mounted within the freezer compartment adjacent the side or rear wall of the freezer compartment such that water and power can be readily supplied to the ice maker. The ice storage receptacle is supported by a shelf structure beneath the ice maker within the freezer compartment. The ice storage receptacle generally extends across the freezer compartment and has a front end adjacent the freezer door. U.S. Pat. No. 4,942,979, to Linstromberg et al. is an example of a prior art ice making system.
In the design of ice maker systems for refrigerators, it is recognized that a control system must be provided for sensing the level of ice disposed in the ice storage bin such that ice pieces are produced when insufficient ice is in the storage bin and ice pieces are not produced when the ice storage bin is filled. A typical ice level sensing system, illustrated by U.S. Pat. No. 5,160,094, to Willis et al., includes an ice maker which employs a bail arm which is periodically lowered into the ice storage bin and then raised back out of the ice storage bin. If the presence of ice pieces interferes with the bail arm being lowered into the ice storage bin, the ice maker is deenergized such that more ice pieces are not produced.
Conventional ice level sensing systems such as the one disclosed by Willis et al. have several drawbacks. Firstly, these mechanical linkage type systems include many moving parts which are subject to failure--particularly in the relatively harsh environment of a freezer. Moving parts may readily become frozen under some circumstances causing the level sensing system to fail. Secondly, conventional ice level sensing systems are not easily applied to a refrigerator ice making system having a door mounted ice storage bin. Door mounted ice storage bins offer several advantages--including making more space available for freezer shelving. However, if a conventional bail arm type ice level sensing system is used with a door mounted ice storage bin, damage may readily occur to the bail arm if the refrigerator door is opened when the bail arm is being lowered into the ice storage bin.
U.S. Pat. No. 3,635,043, to Sterling, is directed to a refrigeration system including a door mounted ice storage receptacle. Sterling discloses having a photoelectric system--employing an incandescent lamp 54 and a photocell 55--for sensing the level of ice in the door mounted bin. The lamp 54 is continuously on and shines a light beam across an ice storage bin. When the beam of light is interrupted by accumulated ice, ice harvesting is prevented. Unfortunately, the system disclosed by Sterling consumes a relatively large amount of energy. Moreover, the incandescent lamp, being continuously on, will have a relatively short life--requiring frequent bulb replacement.
Accordingly, there is a need for robust and effective ice maker control system which may be conveniently employed to sense the level of ice in an ice storage receptacle.